Smart phone users have been urged to be wary of new apps or sanitising products which promise to disinfect a mobile phone.
ANU infectious diseases expert Peter Collignon says apps and devices which claim to clean a phone by using ultrasound or infra-red and ultra-violet light might not really work.
The popularity of smart phones has seen the emergence of products which claim to kill germs found on the devices because of everyday use. A quick search on the internet has found at least half a dozen products.
"It is true that UV light can kill germs," Professor Collignon says.
But he says there's no guarantee the devices will prevent illness.
"Because your hands touch so many other things in the environment, you will still have to wash your own hands," he says.
Professor Collignon says he doesn't want to discourage people from buying the new devices and apps, if they want to.
"But if your phone is only used by you, then your risk of catching a disease only reflects what you've touched."
He says the age-old advice of having good hand hygiene before touching your mouth, nose or eyes, should apply in all situations.